Elan spyder chassis / which engine bushes?

[Pistacchio sprint 72]

Hello, rohan is making me doubt... And doubt is good before ordering!

I thought you had different engine bushes when running a 701m engine and similar bushes when running a 711m casting twink

Rohan might says that if you have a spyder chassis, no matter the engine casting, you can use similar bushes.

I run dellortos if you wondering!

Thanks for your input!

[rgh0]

let go back to first principles.

The high lift mount on the carb side of an Elan with a Lotus chassis and standard height 1500 block ( eg 120E, 681F, 701M) was required to ensure the Webers and airbox did not hit the footwell. The standard Anglia mount was used on the exhaust side so the engine had a distinct tilt with the carb side higher than the exhaust side. Note the Plus 2 always used the standard mounts as its footwell clearance is greater. I also understood that Stromberg cars could also use a standard mount both sides as the stromberg carbs and airbox sat higher and cleared the footweel OK but I have never checked that in practice as not many Stromberg cars here in Australia.

If you fit a 711 tall block in a standard lotus Elan chassis then the engine is about 15mm taller and you probably could / should use standard mounts on both sides to ensure the engine does not hit the bonnet and as the engine is taller the carbs should clear the footwell OK. The 711 block is also wider across the engine mounts on the block casting and this needs to be allowed for with shorter spacers on the exhaust mount side or by machining the block engine mount bosses back to the short block width, however this does not affect the mount selection.

If you fit a 701M or other standard height 1500 block in a Spyder chassis the mounts are reversed and the 4 bolt hole side goes onto the chassis and an arm comes from the engine block to the 2 bolt hole side of the mount. The mount is inverted to maintain its fail safe nature in this situation. The Spyder arms are designed to maintain the correct clearance with the footwell without using a high lift mount ( which would actually lower the engine as its inverted). so standard anglia mounts are used on both sides.

If you fit a 711 tall block in a spyder chassis then it may be desirable to lower the engine to maintain bonnet clearance and you could use the high lift mount to lower the engine in that situation if needed.

lots of combinations and permutations to think about

cheers
Rohan

[Pistacchio sprint 72]

Hello Rohan,

When you write " The mount is inverted to maintain its fail safe nature in this situation" do you main the bushes are installed in the U position so if the rubber fails (like it happened to me) the center plate of the bush attached to the arm fell in the bottom of the U?

I contacted Stuart from TTR this morning to order two similar Engine bushes.
I also asked for new screws, rivnuts, washers.....

[Pistacchio sprint 72]

The bolts look like new ones would be fair...

[rgh0]

Hello Rohan,

When you write " The mount is inverted to maintain its fail safe nature in this situation" do you main the bushes are installed in the U position so if the rubber fails (like it happened to me) the center plate of the bush attached to the arm fell in the bottom of the U?

I contacted Stuart from TTR this morning to order two similar Engine bushes.
I also asked for new screws, rivnuts, washers.....

Yes the mount is installed with the outer shell in the U position for the Spyder chassis. The centre plate is bolted to the arm going to the engine so if the rubber fails the centre plate drops to the base of the U and still supports the engine.

cheers
Rohan